feat: add datasource NewEnvSource

datasource/env.go

@@ -0,0 +1,26 @@
+package datasource
+
+import "os"
+
+// envDataSource is a data source that loads data from the environment.
+type envDataSource struct {
+}
+
+// NewEnvSource creates a new envDataSource.
+func NewEnvSource() DataSource {
+	return &envDataSource{}
+}
+
+// Get returns the value of the given key.
+func (envDataSource) Get(key string) any {
+	if key == "" {
+		return nil
+	}
+
+	value := os.Getenv(key)
+	if value == "" {
+		return nil
+	}
+
+	return value
+}